This invention relates generally to a receiving device with timekeeping function and, in particular, to a wireless receiver for receiving time related information carried by electromagnetic waves for updating at least two different times of day displayed by the receiver.
A conventional receiver for receiving a selected signal having a manually adjustable timekeeping function is well known in the art. Since the timekeeping function does not always reflect the correct time of day, adjustment thereto is required on occasion. The frequency of adjustment is based in part, on the precision of the timekeeping mechanism within the receiver.
It is anticipated that services will be provided in the near future for transmitting electromagnetic waves containing only time related information at specified points in time. Such time related information would be used by the receiver for adjusting the internally measured time to update the same in providing the correct time of day.
Conventional selective signal wireless receivers having timekeeping functions are capable of processing time related information transmitted by the service associated with a single time zone. When the timekeeping function of the receiver includes the times of day for different time zones, the timekeeping function must be manually adjusted in updating the same to provide the correct times of day for those time zones other than the time zone in which the receiver is presently located.
When the receiver is moved to a new time zone, the receiver automatically adjusts the internally measured time based on the new time zone. Since the receiver automatically adjusts the internally measured time based on the time related information broadcasted within and reflecting only the new time zone, the accuracy of the previous (old) time zone is not maintained. Manual adjustment to the receiver to maintain the accuracy of the timekeeping function with respect to the old time zone is required. As a practical matter, the receiver cannot be manually adjusted frequently enough to provide a highly accurate display for the time of day in more than one time zone.
The conventional receiver also cannot be adjusted to other than the correct time of day for the time zone in which the receiver is presently located. In other words, a conventional receiver cannot be set (advanced) ahead of the correct time of day.
It is therefore desirable to provide a selected signal wireless receiving device with timekeeping function in which the time of day for more than one time zone can be accurately and automatically maintained. The timekeeping function should also be capable of adjustment for displaying a time of day which has been advanced by a preset period of time beyond the correct time of day.